DE69519066T2 - Elevator device for preventing the premature closure of sliding doors - Google Patents

Description

This invention relates to an elevator device and in particular to a device for controlling the movement of sliding doors of an elevator car or a car and on a floor or a landing.

In a typical elevator device, an elevator car moves in an elevator shaft between landings or floors, and at each floor, elevator sliding doors and landing sliding doors open simultaneously to allow access to the elevator. Usually, pairs of doors slide apart (when opening) or slide together (when closing). (However, a single sliding door may close against a door jamb in both the elevator car or car opening and the landing door opening.) The following description refers to pairs of sliding doors, but of course the same principles apply to single sliding doors.

As is well known in the art, premature closing of the sliding doors can be prevented by the interruption of a beam, such as an infrared beam, which is transmitted across the elevator door frame or door opening and received by an appropriate receiver or detector connected to a circuit controlling a motor causing the door movement. When the obstruction is removed, there is usually a short delay before the doors are allowed to close. To ensure operation at different heights above the floor (e.g. to ensure detection of children, animals or low objects), multi-beam curtains are installed across the door opening of the elevator car. These typically comprise an array of vertically spaced transmitters (e.g. infrared emitting diodes) arranged on one side of the elevator door opening and which beams to corresponding receivers (e.g. infrared responsive diodes) arranged in a vertically spaced array on the other side of the elevator door opening. The transmitter arrays are in the form of strips mounted adjacent to respective closing edges of the elevator car door, whereby the arrays move with the respective doors and, when the doors are open, create a grid of beams extending horizontally across the elevator door frame. If any beam is interrupted, the energy received by the detector is reduced, thereby triggering the circuit, preventing the door from closing. (NB the term "beam" is used generally to mean any suitable form of energy such as light, sound or radio or high frequency waves and suitable transmitters and receivers therefor.)

Often there is a gap of the order of 100mm between the landing doors and the lift car doors, which gap provides the travel clearance for the lift car in the lift shaft. This gap and the fact that the transmitter and receiver strips are mounted on the lift car doors (i.e. inside the landing doors) can cause the following problem to occur. If an obstruction is present in the closing path of the landing doors, the obstruction will not be detected unless and until it interrupts the multi-beam curtain which extends across the lift car door opening. Consequently, in the event that a passenger does not move forward into the lift car as would be expected, then (for example) the hand of the passenger or a child passenger may accidentally become trapped in the landing doors when they close. While this is an abnormal situation, it is nevertheless necessary to take steps to prevent such incidents from occurring.

Although transmitter and receiver strips could be attached to each of the landing doors of each floor and connected to the circuitry controlling the respective landing doors to prevent such entrapment, this does not provide a satisfactory solution to the problem. It would be very costly to attach such transmitter and receiver strips to the landing doors of each floor and to install the necessary circuitry to control the closing of the landing doors of each floor.

From US-A-4,029,176 an acoustic safety system for automatically operated sliding panel doors, in particular elevator doors, is known which has acoustic wave transmitters and receivers arranged in a row along the leading edge of the moving door. Short bursts of acoustic energy are directed both in front of the door and to one or both sides so as to "sweep" a three-dimensional space in and near the path of the door, which represents a zone of potential danger for persons or objects therein. Reflected energy from persons or objects in the danger zone is usable if received after each transmitted shock during a predetermined time interval representing combinations of door opening distance and other selected parameters, and usable reflections are converted into a control signal to stop and reopen the doors before they hit the person or object at risk.

The problem according to the invention is to improve the detection of an obstacle in the vicinity of the floor door opening without incurring additional significant costs for the elevator device.

An advantage of the invention is that the auxiliary transmitter and receiver need only be mounted on the door(s) of the elevator car, so that if an object in the detection zone of the auxiliary receiver(s) responds to the reflection of a secondary beam, this provides an additional measure to prevent premature closing of the door. This advantage would be provided, for example, in a situation where a passenger is standing in front of the landing doors without entering the elevator. While the invention would detect the presence of such a passenger, the primary beam transmitter and receiver arrangement alone would not do so.

The invention also provides a low cost solution to the above problem because it is only necessary to modify the transmitter and receiver strips of existing elevator equipment and to install a circuit responsive to both primary and secondary beam interruption. All this equipment is normally easily accessible from the elevator car.

The auxiliary transmitters and receivers are advantageously provided in a staggered arrangement so that response to any directly received secondary beam emission is reduced or eliminated, particularly when the doors are closing. Such a staggered relationship may be provided in a vertical arrangement by arranging the auxiliary transmitters and receivers at different heights above floor level.

The intensity of the radiation received by the primary receivers increases as the door or doors of the elevator car close. In the preferred embodiment of the invention, the circuit includes a gain adjuster responsive to the strength of the primary beam signal for adjusting the gain in processing the secondary beam signals. For example, the gain is reduced as the doors close so that the sensitivity of the auxiliary receivers is reduced.

Preferably, each auxiliary transmitter and receiver has a field of view or field of influence which is inclined at an angle to the plane of the door opening of the elevator car, an overlapping zone of said field of view or field of influence being the detection zone from which a reflection from an object can be received. In the case of directional transmitters and receivers, these may be inclined at approximately 45º to the plane of the door opening of the elevator so that their directional axes intersect at a point which is a predetermined distance from the landing door or doors. The secondary beam of the auxiliary transmitter or transmitters may diverge and the field of view or field of influence of the auxiliary receiver or receivers may also diverge, thereby increasing the size of the detection zone. Of course, the detection zone gradually moves towards the door opening of the elevator car or lift cage when the doors close if the auxiliary transmitters and/or receivers move with the doors of the elevator car or lift cage.

Shields may be provided to prevent "crosstalk" between the primary and secondary beam systems.

It is possible to use two or more groups of auxiliary transmitters and receivers arranged at different angles to the primary transmitters/receivers. This creates detection zones in different Distances from the doors. Since each detection zone moves towards the doors as they close, it is possible for the zone to "outrun" or "outrun" a passenger approaching the doors and not detect his or her presence. By having two or more auxiliary groups at different angles, it is possible to switch between the groups to counteract the retreating motion of the detection zones. This makes it possible to detect objects during the later or final stages of door closing. In addition, the use of multiple auxiliary groups makes it possible to obtain information about the motion vector of an object. If an auxiliary group with a detection zone closer to the doors detects an object before an auxiliary group with a detection zone further away, then the object is moving away from the elevator and can be ignored. If the group with the outer detection zone makes the detection before the group with the inner detection zone, then the object is moving towards the elevator and the doors should be operated to reopen.

An embodiment of the invention will now be described with reference to the accompanying schematic drawings in which:

Fig. 1 is a plan view of an elevator device according to an embodiment of the invention;

Fig. 2 is a front view showing the positions of the transmitters and receivers; and

Fig. 3 is a block diagram.

Referring to the drawings, an elevator car (not shown) has elevator car doors 1 which are spaced from the landing doors 3 by a clearance gap 2. The gap 2 represents approximately the elevator shaft in which the elevator travels, although the clearance is normally less than that shown in the drawing.

Adjacent to the closing edge of each elevator door 1 are strips 4 and 5, respectively. Each strip is C-shaped in cross-section and has an array of vertically spaced transmitters or receivers. Only one of each is shown in the cross-section. The strip 4 has transmitters 6, such as infrared light emitting diodes. Each of these emits a thin, narrow primary beam 7 to a corresponding primary beam receiver 8, such as an infrared light sensitive photodiode. The beam 7 is one of a plurality of beams which extend horizontally across the door opening of the elevator car, thereby creating a multi-beam curtain. A circuit (not shown) connected to the receivers 8 is triggered by interruption of the beams 7 when a passenger enters the elevator. This prevents the door from closing, as explained above.

Auxiliary transmitters 9 and auxiliary receivers 10, which may be similar infrared diodes, are arranged in the respective strips 4 and 5, respectively. The auxiliary transmitters 9 transmit respective secondary beams of (e.g.) infrared radiation, but these beams are not received directly by the receivers (since they are not in the optical paths of the transmitters 9). The secondary beam 11 is emitted at an angle (e.g. about 45º) to the primary beam axis 7 towards a zone in front of the floor doors 3. In the absence of any object, such as a passenger 12, no reflection of the secondary beam is obtained by auxiliary receivers 10a, 10b, 10c. However, when a passenger 12 enters the detection zone 13, which is represented by overlapping fields of view or fields of action of the transmitter 9 and receiver 10 (the receiver 10 is arranged at a similar angle, e.g. at about 45º to the primary beam axis 7), the secondary beam 11 falls on the passenger's body and reflected radiation 14 is received by one or more of the auxiliary receivers 10a, 10b, 10c. Consequently, even though the passenger 12 has not interrupted the primary beams 7, the secondary receivers 10 respond to trigger the circuit to prevent the door from closing.

The transmitters 9 and receivers 10 are preferably staggered as shown in Fig. 2 by being located at different heights above ground level. As shown in the drawing, the receiver 10b is located midway between transmitters 9a, 9b (etc.) as shown in Fig. 2. The staggered relationship helps prevent any false response by secondary beam receivers 10a-10c which would otherwise occur due to direct reception of any secondary beam radiation. However, this does not prevent the auxiliary receivers from receiving secondary beam radiation reflected from an object because this radiation is reflected at different angles (i.e. reflected or scattered by the body of a passenger or other object) and some of the radiation will reach or enter one or more of the secondary beam receivers 10a-10c.

Masks or shields 15 are arranged adjacent to each of the auxiliary transmitters and receivers 9, 10 so that they are shielded from primary beam radiation. The auxiliary receivers 10 are also angled from the path 7 of the primary beam and in view of this and the use of shields, the auxiliary receivers are arranged so that they do not receive direct primary radiation.

The principles described above, i.e. the use of both secondary beam and primary beam radiation, can be used with circuitry of various types, so long as the reflected signals from secondary beams are used to trigger means for preventing premature door closing as explained above. However, a brief description will now be given of a circuit as shown in Fig. 3 which was used in a preferred embodiment of the invention. Fig. 3 shows a block diagram which represents a simplified version of a preferred detector system. In practice, many of the functions would be carried out by suitable software running on a microcontroller. run at the core of the control circuit, but these functions are shown in an equivalent "hardware" version in Fig. 3 (for purposes of explanation).

In operation, the beam multiplexer 16 is used as a "master clock" of the system and determines which detection function is operated and which beam of a radiation pattern is selected. These detection functions are broadly those associated with the use of the primary beam or the secondary beam. For example, in a primary beam mode, a group of transmit diodes 6 are turned on and the equivalent group of receive diodes 8 are activated so that they receive primary beam radiation and provide a trigger signal when the primary beam is interrupted. For example, there may be five groups, each of which has eight pairs of transmit diodes and receive diodes, with each group being turned on sequentially in turn so that a total of 40 primary beam diode pairs are scanned. After scanning the five groups of primary beam diode pairs, the secondary beam diode pairs (or auxiliary transmitters and receivers) are scanned. In this case, all of the auxiliary transmitters 9 and auxiliary receivers 10 are turned on because it is not necessary to scan the auxiliary diode pairs separately (or in groups). For example, three diode pairs may be provided in the secondary beam system. Thus, a cycle can be completed in which five groups of primary diodes and one group of secondary diodes are scanned or monitored before the cycle is repeated. Various scanning patterns can be used according to requirements.

When the multiplexer 16 selects the direct or primary beam patterns, the output of the selected groups of transmit diodes is modulated with (for example) a square wave of approximately 15 kHz and the corresponding receive diodes 8 are monitored by connecting the beam to a receive amplifier 17. The output of the amplifier 17 is fed to a synchronous detector 20 via a gain control circuit 18 in which the signal is rectified and converted into a DC voltage proportional to the received signal strength. During a scan cycle, as the groups of primary beam diode receivers are monitored sequentially, a signal level monitor 18 collects an "average" received signal level. If this average value is more or less than the preset threshold, it is used to change the gain control 18 to bring the average into the acceptable "window" of voltage. Any beams which still fall outside this "window" (at the lower end) are considered "blocked". A "direct beam missing" detector 20 generates a signal to indicate to an "obstacle detected relay driver" 21 that the door motor output is switched to "STOP" or "REVERSE", thereby preventing the door from closing.

When the multiplexer 16 selects the secondary beam system or the "reflected beam system", the signal level monitor 19 "remembers" the set gain when the primary beams or direct beams were used and thereby provides an indication of the width of the door opening (when closing). This "remembered" gain is used as a reference value for the monitor 19 to preset the gain control 18 to match known characteristics of the reflective system and thereby avoid having too much or too little gain for successful detection of obstacles 12 within the reflective beam convergence zone 17. This feedback of information from the direct beam system or primary beam system therefore enables successful operation of the reflective system in the preferred embodiment of the invention. In other words, the signal from the primary beam system is used to reduce the gain or sensitivity of the secondary beam detection system so that the door closing does not occur accidentally by receiving radiation other than that reflected or scattered by an object in the convergence zone 13.

If a reflective obstruction is present in zone 13, then the reflected signal, which is processed by amplifier 17, gain control device 18 and synchronous detector 24, exceeds a preset trigger threshold and a "reflected beam increase" detector 22 responds by activating a relay driver 21 to prevent door closing. If a person may be in the convergence zone 13 but does not wish to enter the elevator car, a "pause" function device 23 may be operated after a short delay to allow the doors to close normally. Alternatively, the interruption of the direct beam pattern 7 may be used as a signal that passengers are entering or leaving the elevator car, so that triggers from the reflection detector (using beams 12, 14) may operate or be ignored as appropriate. For example, when a passenger exits the elevator car, the direct beams are first interrupted and subsequent reflected detections are ignored (because the passenger exits the elevator car). In other circumstances, a trigger from the reflective detector which is not followed within two seconds (e.g.) by a trigger from the direct detector may be ignored as negligible and the reflective system may be briefly rendered inoperative to prevent a delay in the movement of the elevator car. In short, the reflective system (12, 14) is only necessary during the early part of door closing because it is not possible for a passenger to enter the elevator car if the doors have already closed to some extent. Therefore, the secondary beam system can be effectively shut down or desensitized when the doors are closed to a certain extent (e.g. half closed) to prevent the secondary beam detectors (10) from responding to negligible radiation (since the level of radiation increases when the doors close), thereby unnecessarily switching off the Closing of the door is prevented. This would prevent the doors from opening and closing violently as a result of negligible jet effects.

Although one form of circuit has been described above, this is done merely as an example of how the principles of the invention may be used and other circuits may embody the principles of the invention while not having all of the features described with reference to Figure 3.

Claims (12)

1. Elevator device with an elevator car or a lift car with two oppositely movable doors (1) which move across a door opening of an elevator car or a lift car; an elevator shaft in which the elevator car or the lift car (1) moves between floors, the elevator shaft having at least one sliding door (3) on each floor; primary transmitting or devices (6) which are attached to the elevator car or the lift car (1) for transmitting primary energy across the door opening of the elevator car or the lift car; primary receiving devices (8) which are attached to the elevator car or the lift car (1) for receiving the primary energy; a circuit (16-21) which is connected to the primary receiving devices (8) to prevent door closing; and one or more auxiliary transmitters and receivers (9, 10) mounted on the elevator car (1) such that when the elevator car doors and the landing doors (1, 3) are open, each auxiliary transmitter (9) transmits secondary energy into a detection zone outside the elevator car and in front of the landing door or doors (1, 3) such that an object in the detection zone reflects some of the secondary energy to the auxiliary receiver (10), characterized in that said primary means (6) and said primary receiver means (8) are mounted on opposite doors (1) and said primary transmitter means (6) transmit an infrared primary beam or beams (7) across the door opening of the elevator car to the primary receiver means (8) which are responsive to the absence of the infrared primary beam or beams (7) as a result of interruption by said object, to generate a door open signal; said auxiliary transmitter (9) is mounted on one of the doors of the elevator car (1) so as to direct a second infrared beam or beams into the detection zone. and said auxiliary receiver (10) is mounted on the other door (1) and is arranged not to respond to any direct infrared secondary beam emission but only to a reflected secondary beam from the object in the detection zone to generate a door open signal; the circuit (16-21) for preventing door closing is activated when the infrared primary beam or beams (7) are not received by the respective primary receiving means (8) and/or when any infrared secondary beam is received by said auxiliary receiver (10). 2. Elevator device according to claim 1, in which the auxiliary transmitters and receivers (9, 10) are arranged in a staggered relationship. 3. Elevator device according to claim 1 or 2, wherein the circuit (16-21) has a gain adjustment device (19) which responds to the strength of the primary beam signal in order to set or adapt the gain when processing the secondary beam signals. 4. Elevator apparatus according to claim 3, in which the gain is adjusted so that the sensitivity of the secondary beam receiver to unwanted or interfering signals is reduced when the doors close. 5. Elevator apparatus according to any preceding claim, wherein each auxiliary beam transmitter and receiver has a field of view or impact field on an axis which is inclined at an angle to the plane of the door opening of the elevator car, and wherein the secondary infrared beams are directed or transmitted outwardly away from the plane of the door opening of the elevator car so that an overlapping zone of the fields of view or impact fields corresponds to the detection zone, and so that the detection zone is spaced from the closing plane of the landing doors when they are open. 6. Elevator device according to claim 5, wherein the directional axes of the auxiliary beam transmitters and receivers are inclined at approximately 45º to the plane of the door opening of the elevator car or cabin. 7. Elevator device according to one of claims 1 to 4, which has two or more groups of auxiliary beam transmitters and receivers, the directional axes of each group assuming different angles to the plane of the door opening of the elevator car or the elevator car, so that locking zones are created at different distances from the doors. 8. Elevator device according to claim 7, which comprises means for switching between said groups of detectors to counteract a retractive movement of the detection zones when the doors close. 9. Lifting device according to claim 7, which comprises means for obtaining information about the motion vector of the object. 10. An elevator apparatus according to any preceding claim, wherein shields are arranged adjacent to the auxiliary beam transmitters and receivers so that any secondary beam radiation is prevented from being directly received. 11. An elevator apparatus according to any preceding claim, wherein the primary beam transmitters and auxiliary beam transmitters are arranged in a vertically spaced array on one side of an elevator car door opening and the primary beam and auxiliary beam receivers are arranged in a vertically spaced array on the other side of the elevator car door opening. 12. Elevator apparatus according to claim 11, wherein the vertically spaced arrangements are arranged on the closing edges or adjacent thereto of a pair of sliding doors on the elevator car or the elevator car.